Question

A bulb can't be used in place of a resistor to verify Ohm's law. Why?

Answer 1

A light bulb is a device that produces light from electricity.The light bulb turns electricity into light by sending the electric current through a thin wire called a filament, which are mostly made up of tungsten, a metal. The resistance of the filament heats the bulb up. Eventually the filament gets so hot that it glows, producing light.so here when current flows through the bulb, causes the change in temperature which inturn cause a change in the resistance.
The essential condition of the Ohm's law is that a changing temperature does not affect the resistance , since in bulb when temperature changes, resistance also changes,hence we cannot use bulb in place of a resistor to verify Ohm's law.